Wrapping machine



Sept. 16, 1969 SCHAEFER ET AL 3,466,849

WRAPPING MACHINE 12 Sheets-Sheet 1 Filed Nov. 16, 1965 OMLU'Hansen R0bev'if fc Fiche)",

E. J. SCHAEFER ET AL Sept. 16, 1969 WRAPPING MACHINE Sept. 16, 1969 E.J. SCHAEFER ET AL H 3,466,849

WRAPPING MACHINE Filed Nov. 16. 1965 12 Sheets-Sheet 5 Sept. 16, 1969 AF ET AL 3,466,849

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Sept. 16, 1969 Filed Nov. 16, 1965 E. J. SCHAEFER ET AL WRAPPING MACHINE12 Sheets-Sheet 6 Sept. 16, 1969 E, J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE 12 Sh tsShe et 7 Filed I f I Z 5 o I I 2 7 5 O 5 319/a2 L/ Z L M 322 F 316 323 Q at Se t. 16, 1969 E. J. SCHAEFER ET AL3,466,849

WRAPPING MACHINE Filed Nov. 16, 1965 12 Sheets-Sheet a 717 Pr fi P 6,1969 E. J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed Nov. 16, 1965 12 Sheets-Sheet 9 Sept. 16,1969 5,CHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed NOV. 16. 1965 12 Sheets-Sheet 10 SUCTION PUMPSept. 16, 1969 E. J. SCHAEFER ET AL 3,466,849

WRAPPING MACHINE Filed Nov. 16, 1965 12 Sheets-Sheet 11 J54 IK/353 121.0

352 JQlb 63b kfi D O United States Patent 3,466,849 WRAPPING MACHINEEdward J. Schaefer and Omar Hansen, Jr., Blutfton, and

Robert F. McVicker, Anderson, Ind., assignors to Franklin Electric Co.,Inc, Bluliton, Ind., a corporation of Indiana Filed Nov. 16, 1965, Ser.No. 508,026 Int. Cl. B6511 11/00, 49/00, 7/04 US. Cl. 53210 27 ClaimsABSTRACT OF THE DISCLOSURE There are presently on the market machinesfor automatically wrapping articles in a thin transparent film. Such amachine is described in the copending patent application of Omar Hansen,Jr., et a1. Ser. No. 363,954, filed April 30, 1964, the machinedescribed therein being designed for use primarily as a fresh meatwrapper in a supermarket.

Cellophane has been commonly used as the protective film, and themachine described in the Hansen et a1. patent application works verywell with such a film. Newer plastic materials, such as polyolefin, havebecome available for use as the film, which are less expensive thancellophane, and consequently more desirable. Polyolefin is howeverdifiicult to handle because it is very thin and, more important, itusually is electrically charged. When charged, this type of film clingsto other materials such as metal and, if it becomes folded upon itself,it is very difiicult to straighten. One way in which such a film hasbeen used has been to cut the film into sections having the approximatesize necessary to wrap a series of articles, and then wrapping thearticles in the sections by a combination of manual and automaticoperations. Such a system is of course more costly and time consumingthan a fully automatic wrapping system wherein the film is taken from asupply roll of the film material and automatically wrapped around thearticles and automatically cut to sections having the right dimensionsfor the articles being wrapped.

Accordingly, it is an object of this invention to provide an automaticwrapping machine, capable of handling thin plastic films, such aspolyolefin.

Another object is to provide a machine of the above character, includinga novel film feed mechanism for stripping the film from a supply rolland maintaining the film under tension during a wrapping cycle.

A further object is to provide a machine of the above character,including novel means for controlling the free end portion of the filmafter a section of film has been girdle wrapped around an article andsevered.

A still further object is to provide a machine of the above character,including novel means for heat sealing the section of film which hasbeen wrapped around the article.

Other objects and advantages of the invention will be apparent from thefollowing description taken in conjunction with the accompanying figuresof the drawings, in which:

FIG. 1 is a side elevational view of awrapping machine embodying theinvention with some parts partially broken away;

FIG. 2 is an enlarged fragmentary view of a portion of the machine;

FIG. 3 is an end elevational view of the structure shown in FIG. 2;

FIG. 4 is a further enlarged sectional view taken on the line 44 of ofFIG. 3;

FIG. 5 is an enlarged fragmentary view of another portion of the machineshown in FIG. 1;

FIG. 6 is a further enlarged fragmentary view of a portion of thestructure shown in FIG. 5;

FIG. 7 is a fragmentary end elevational view of a portion of thestructure shown in FIG. 6;

FIG. 8 is a fragmentary sectional view of a portion of the structureshown in FIGS. 6 and 7;

FIG. 9 is an enlarged fragmentary view of another portion of the machineshown in FIG. 1;

FIG. 10 is a further enlarged fragmentary sectional view taken on theline 1010 of FIG. 9;

FIG. 11 is a further enlarged fragmentary sectional view taken on theline 11-11 of FIG. 9;

FIG. 12 is a sectional view taken on the line 1212 of FIG. 11;

FIG. 13 is an enlarged fragmentary view of another portion of themachine shown in FIG. 1;

FIG. 14 is a plan view of the structure shown in FIG. 13;

FIG. 14a is a fragmentary view of a portion of the structure shown inFIGS. 13 and 14;

FIG. 15 is a sectional view taken on the line 1515 of FIG. 16;

FIG. 16 is an enlarged fragmentary view of another portion of themachine shown in FIG. 1;

FIGS. 17 to 23 are schematic illustrations showing the operation of themachine of FIG. 1;

FIGS. 24 to 28 are schematic illustrations showing an alternative formof a portion of the machine;

FIGS. 29 to 33 are schematic illustrations generally similar to FIGS. 24to 28 but showing another alternative form of the portion of themachine; and

FIGS. 34 to 42 are schematic illustrations generally similar to FIGS. 24to 28, FIGS. 29 to 33, but showing still another alternative form of theportion of the machine.

In general, a wrapping machine embodying the invention is generallysimilar to the wrapping machines described in the above-mentionedcopending patent application Serial No. 363,954, and copending patentapplication Serial No. 219,482, filed August 27, 1962 (now Patent3,248,848) in the name of Carl Littlefield. A machine of this charactercomprises a wrapping mechanism, an input mechanism for conveyingarticles to be wrapped to the wrapping mechanism, and a film supply andtransport mechanism for feeding film into the wrapping mechanism, thelatter mechanism wrapping the article in a section of the film andsealing the section of film around the article.

The film supply and transport mechanism comprises means for supporting asupply roll of the film, means for stripping film from the supply roll,means for transporting the film to the wrapping mechanism, and meansproviding a reserve supply of film under tension between the filmstripper and the Wrapping mechanism. As an article is being wrapped bythe wrapping mechanism, film is drawn from the reserve supply, therebygradually depleting it. When the reserve supply has been depleted to apredetermined length of film, a drive motor connected to the supply rolland to the film stripper is automatically energized to feed film fromthe supply roll into the reserve supply to a sufficient extent toreplenish the reserve supply. The drive motor is later automaticallyturned off when the reserve has been replenished, and remains off untilthe reserve supply has again been depleted. The film in the reservesupply is maintained under tension, the means for maintaining tensionalso serving to switch the drive motor on and ofl.

The film supply and transport mechanism further includes means forvertically suspending a length of film adjacent the wrapping mechanism,the latter mechanism being operable to receive an article from thearticle input mechanism and positioning the article adjacent the lengthof film and above the lower or free end of the film. The article is thenmoved horizontally in the forward direction against the film, causingthe article to slide over a portion of the film and rest on the free endof the film. The article, and the portion of the film under it, are thenmoved upwardly, which movement causes the film to be folded over the topof the article and downwardly on the rearward side of the article due tothe combination of the upward movement of the article and a dancer rollwhich pulls the film tightly over the top of the article and downwardlyat its rearward side. The article is then moved horizontally in therearward direction, causing the film at the rearward side of the articleto be drawn underneath the article and to overlap its free end. Movementof the article in the rearward direction is halted momentarily while theoverlapped portions of the film are over a tack sealer, and after thetack sealing operation has been completed, the section of film aroundthe article is cut off or severed from the supply. In a preferred formof the invention, the dancer roll and a blow tube are then operable toprevent the free end portion of the film from falling or folding back onitself, or from clinging to adjacent portions of the mechanism, and tocause a new length of film to be vertically suspended in preparation fora subsequent wrapping cycle or operation.

The film tends to stick to hot surfaces, and to prevent the film fromsticking to the tack sealer, the portion of the sealer contacting thearticle is made movable with the article. After the overlapped portionsof the section of film have been tack sealed and the film cut, thearticle is moved through an end folding mechanism which folds the endsof the film underneath the article and moves the article to a mainsealer. Again, the film is prevented from sticking to the main sealer bymaking the portion of the main sealer contacting the article movablewith the article. After the article has passed the main sealer, itarrives at an output station which may have any desired form.

In greater detail, the wrapping machine comprises a frame 50 (FIG. 1)including two laterally spaced plate members 51 and 52 which are securedtogether by suitable braces and are mounted on wheels 53 for movement onthe floor. Mounted on the frame between the plate members 51 and 52 arean article input mechanism 54, a wrapping mechanism 56. and a filmsupply and transport mechanism 57.

The article input mechanism 54 is shown as being in the form of a chainconveyor and includes two pairs of laterally spaced sprockets 58 and 59and two laterally spaced chains 61 which mesh with the sprockets 58 and59. Attached between the two chains 61 are a series of runners orpushers 62 which push articles placed between the chains 61 from left toright, or in the rearward direction, as the chains 61 are rotated in theclockwise direction. An article to be wrapped is placed on a horizontalplate 63 between a pair of laterally spaced, longitudinally extendingguides 64, and between adjacent pushers 62, and one of the pushers 62engages the article and pushes it along the upper surface of the plate63 in the rearward direction into the wrapping mechanism 56. A drivemechanism is connected to rotate the sprockets 58 and 59, and the chains61 and the pusher 62 which may be of the character described in theabove-mentioned patent applications or any conventional drive. Forexample, the sprockets 58 and 59 may be connected to laterally extendingshafts 66 which are rotatably mounted on the frame 50 between the plates51 and 52, and connected by a suitable chain and sprocket arrangement toa main drive motor (not shown in FIG. 1) also mounted between the twoplate-like members 51 and 52 generally below the input mechanism 54. Itis preferred that the main drive motor for the input mechanism 54 alsobe connected to operate the wrapping mechanism 56 so that the rate ofrotation of the chains 61 and the positions of the pushers 62 willalways have a predetermined relation with the rate of operation and thepositions of the parts of the wrapping mechanism 56, and consequentlythe two rates may be adjusted simultaneously.

The wrapping mechanism 56 comprises a bottom elevator 71 and a topelevator 72 which are supported by two pairs of arms or bars 73 and 74,one bar of each pair being shown in FIGS. 1 and 5. One bar of each pairis pivotally connected to one side of each of the elevators 71 and 72,and at substantially their centers the bars 73 and 74 are also pivotallyconnected to the frame of the machine as by pins 76 (FIG. 1). At leastone, and preferably two, vertically extending links 77 are provided,which extend downwardly from the lower bars 73 and are connected to bemoved substantially vertically in a reciprocating motion by a drivemechanism, which as previously stated is preferably the same drivemechanism as that provided for the input mechanism 54. A suitable drivefor the elevators 71 and 72 and the bars 73 and 74 is described in theabove-mentioned patent applications, and comprises a cam which isconnected to be rotated by a drive motor, and cam follower which isconnected by suitable means to the link 77, the construction of the camand the linkage being such that the link 77 is moved periodically up anddown in a reciprocating motion.

Movement of the link 77 causes the two elevators 71 and 72 to swingbetween horizontally aligned, intermediate positions shown in dashedlines in FIG. 1, and vertically displaced positions shown in full linesin FIGS. 1 and 5. The elevators 71 and 72 have substantially flat plates78 and 79, respectively, which form article supporting surfaces andwhich are always horizontal because the bars 73 and 74 form parallelarms. \Vhen the elevators 71 and 72 are at the intermediate position,the plates 78 and 79 are at substantially the same level, as shown indashed lines in FIG. 1. When the elevators 71 and 72 are at thevertically displaced positions, the upper surface of the plate 78 issubstantially at the level of the upper surface of the plate 63 of theinput mechanism 54, and the upper surface of the plate 79 of theelevator 72 is substantially at the level of a plate 81 (see FIG. 1) ofan end folding and sealing apparatus 316 of the wrapping mechanism 56.

The wrapping mechanism 56 further includes plunger means for moving anarticle being wrapped from the bottom elevator 71 to the top elevator 72when the two elevators are at the intermediate position, and also formoving the article from the top elevator 72 to the plate 81 when the twoelevators are in the vertically displaced positions. As described in thepreviously mentioned Hansen et al. patent application, the plunger meanscomprises a top plunger 82 and a bottom plunger 83. The top plunger 82is fastened to a slider 84 which is movable longitudinally of themachine on a suitable guide means 86, while the bottom plunger ismounted on another slider 87 which is also mounted for longitudinalmovement on the machine on another guide means 88. A link 89 extendsbetween and is connected to the two sliders 84 and 87, and a suitablecam actuated mechanism, described in the above-mentioned Hansen et al.patent application, is provided for periodically moving the sliders 84and 87, and the plungers 82 and 83 attached thereto, longitudinally ofthe machine in synchronism to move the articles as previously described.The mechanism for operating the plungers 82 and 83 is constructed suchthat the movement of the plungers is synchronized with the movement ofthe two elevators 71 and 72. When the two elevators are at theintermediate position, the two plungers 82 and 83 move toward the left,or forwardly, as seen in FIGS. 1 and 5, the plunger 83 moving an articlefrom the bottom elevator 71 to the top elevator 72, and when the twoelevators are in the vertically displaced positions, the two plungers 83and 82 move toward the right, or rearwardly, the plunger 82 moving anarticle from the top elevator to the plate 81.

The bottom plunger is preferably in the form of a rake, having aplurality of downwardly extending teeth which sweep across the uppersurface of the plate 78 of the bottom elevator 71 and engage therearward side of an article being wrapped when the plunger 83 is movedforwardly, in order to move an article from the bottom elevator to thetop elevator. The top plunger 82 may be a simple rod-like member whichangles downwardly and rearwardly as shown in FIG. 1, the lower end ofthe plunger 82 being at substantially the lateral center of the plate 79of the top elevator 72. The top elevator 72 is preferably provided witha floating or longitudinally movable receiver bar 91 which is mountedsuch that it is capable of being moved longitudinally of the machine atsubstantially the lateral center of the plate 79. As described in theHansen et al. patent application, the receiver bar 91 comprises agenerally rectangular block 90 (FIG. 5) which is connected to the plate79 by a nut and bolt arrangement 95 in a manner such that the amount ofsliding friction between the block 90 and plate 79 may be adjusted. Anangle shaped bracket 92 is preferably secured to the rearward side ofthe block, one arm of the bracket extending generally vertically and theother arm of the bracket being positioned to extend under the bottom ofan article being wrapped adjacent its forward edge. As will be describedhereinafter, the film being Wrapped about the article is caught betweenthe bracket 92 and the article. When the article being wrapped is pushedby the bottom plunger 83 from the bottom elevator 71 to the top elevator72, the forward side of the article engages the bracket 92 and pushesthe bracket and the block forwardly of the machine and, subsequently,when the article is pushed by the top plunger 82 rearwardly of themachine, the plunger 82 engages the block 91 and pushes it and thearticle toward the right, or rearwardly until the article is depositedon the plate 81.

As described in the previously referred to Hansen et al. patentapplication, mounted on the upper surface of the plate 79 of the topelevator 72 are a pair of laterally spaced end folders 96, which arelaterally adjustable, relative to the plate 79 depending upon the widthof the article being wrapped. The folders 96 are shaped to engage thefilm at the lateral ends of the article and fold the film at the ends ofthe article as the article is being pushed from the bottom elevator 71to the top elevator 72.

Further, as the top elevator 72 is being moved upwardly during wrappingcycle, the film is stretched tightly across the upper surface of thearticle so that there is a tendency for the taut film to pull thearticle rearwardly off of the plate 79 of the top elevator. To preventthis, a rake-like bracket 97 (FIG. 5) is provided, having a plurality togenerally vertically extending stop fingers 98 (FIG. 5) which arelocated adjacent the rearward edge of the plate 79 of the top elevator.The bracket 97 is mounted underneath the plate 79, for pivotal movementrelative to the top elevator, by means of a shaft 99, and a tensionspring 101 is connected to the bracket 97 at the end of the bracketwhich is opposite from the fingers 98, and to the top elevator 72. Thespring 101 urges the fingers 98 in the counterclockwise direction asseen in FIG. 5, or upwardly. Slots are formed in the rearward edge ofthe plate 79 and the fingers 98 normally extend through these slots.

To retract the fingers 98 below the upper surface of the plate 79 wheneither an article is being moved on to the top elevator 72 or beingmoved ofi of the top elevator 72, a bottom actuator 102 and a topactuator 103 are provided. The bottom actuator 102 is mounted on theplate 63 of the input mechanism 54 and extends upwardly therefrom to aposition where it engages the bracket 97 forwardly of the shaft 99 andthereby pivots the bracket 97 in the clockwise direction to retract thefingers 98 when the top elevator 72 is at the intermediate position. Theheight of the bottom actuator 102 is adjusted such that the bracket 97will be pivoted to lower the fingers 98 below the upper level of theplate 79. When the top elevator 72 is moved toward its upper position,the bracket 97 moves out of engagement with the bottom actuator 102 andthe fingers 98 move upwardly and hold the package on the plate 79. Whenthe elevator 72 reaches the upper position, the top actuator 103 engagesthe bracket 97 forwardly of the shaft 99 and pivots the bracket 97 inthe clockwise direction as seen in FIG. 5 and again causes the fingers98 to be retracted below the upper level of the plate 79, therebypermitting the article to be pushed off the top elevator 72 and on tothe plate 81. Of course, as soon as the top elevator 72 again movesdownwardly, the bracket 97 moves out of engagement with the top actuator103 and the fingers 98 again move upwardly above the upper surface ofthe plate 79.

The wrapping mechanism 56 further includes scissorlike means forsevering the film after it has been wrapped around an article and tacksealed. The severing means comprises a horizontal, laterally extendingstationary blade 106 (FIG. 5) which is fixed to the frame of the machinejust below and forwardly of the forward edge of the plate 81. Thesevering means further includes a pair of movable blades 107 carried bythe top elevator 72 on the underside thereof and at the rearward edge.The movable blades 107 are carried by brackets 108 and extend laterallyof the machine in end-to-end relation. As described in the copendingHansen et al. application, the two blades form a V with the apex of theV being toward the left and at substantially the lateral center of thetop elevator 72. From the apex, each of the blades 107 extends laterallyof the machine and rearwardly, and each of the blades also slopesdownwardly a slight amount from its apex. When the top elevator 72 movesto its upper position, the outer lateral ends of the blades 107 contactthe underside of the stationary blade 106, and when the brackets 108 aremoved rearwardly, the downward and rearward slant of each of the blades107 causes the blades to be in point-to-point contact only with thestationary blade 106. This produces a scissors-like action whichprevents tearing or pulling of the film while it is being severed. Thebrackets 108 are mounted for pivotal movement on the top elevator 72 bya laterally extending shaft 109 which is fastened to the top elevator72, and a tension spring 111 connected between the forward end of thebracket 108 and the top elevator 72 urges the bracket 108 and the blades107 upwardly, or in the counterclockwise direction as seen in FIG. 5.The shaft 109 is also mounted for longitudinal movement relative to thetop elevator 72, and as described in the abovementioned copending patentapplications, after the top elevator 72 has moved to its upper position,an article on the top elevator has been pushed rearwardly by the plunger82, and the film has been tack sealed, the bracket 108 and the shaft 109and the blades 107 are moved rearwardly to sever the section of filmaround the article. The mechanism for moving the rod or shaft 109, andconsequently the bracket 108 and the blades 107, longitudinally of themachine comprises a suitable cam 112 and cam follower 113 mechanism(FIG. 5) which is preferably also actuated by the main drive motor insynchronism with the movements of the elevators and the plungers.

The film, indicated by the reference numeral 121 in FIG. 1, for wrappingan article, is delivered to the wrapping mechanism 56 by the film feedand transport mechanism 57 which comprises an arbor 122 (FIGS. 1 to 3)for supporting a supply roll 123 of film, the arbor 122 being connectedto be driven by a motor-gear box unit 124. As described in detail in thecopending Hansen et al. patent application, the arbor 122 comprises acylindrical tube 126, the outer diameter of which is slightly less thanthe inner diameter of the supply roll 123 so that the roll 123 mayeasily be slipped over the arbor 122. The tube 126 is connected to themotor-gear box unit 124 by a drive shaft (not shown) which extendsthrough a support tube 127, the latter tube extending through a holeformed in a mounting plate 128. The plate 128 is secured to the frame ofthe machine, and the motor-gear box unit 124 is secured to one side ofthe plate 128 while the arbor 122 is rotatably fastened to the supporttube 127 and extends laterally of the machine from the other side of theplate 128. The drive shaft extends through the support tube 127 and intothe tube 126 and has a driving connection therewith. A series of slots131 are formed through the wall of the tube 126 and a plurality ofradially movable fingers 132 extend through the slots 131 and areadapted to grip the inner periphery of the supply roll 123 when the rollis positioned on the tube 126 and the fingers 132 are radially extended.The fingers 132 are connected for movement radially inward or outward toa mechanism having a manually operated actuating knob 133 at the freeend of the tube 126. 7

With a film of the character herein contemplated, the film tends tocling to itself on the supply roll 123. To avoid this difficulty astripper roller 136 is provided, the stripper roller pulling the filmoff the supply roll 123. To this end, the stripper roller 136 is mountedon the plate 128 and connected to be driven by the motor-gear box unit124 (FIGS. 1 to 4). With reference to FIG. 4, the stripper rollers 136comprises a shaft 137 having one end extending through a hole 138 formedin the mounting plate 128. The diameter of this end of the shaft 137 isreduced to form a shoulder 139 and the reduced diameter end portion ofthe shaft 137 is externally threaded to receive a nut 141 and a washer142. To rigidly secure the shaft 137 to the plate 128, this end of theshaft 137 is placed in the hole 138 with the shoulder 139 abutting themargin of the hole 138, at one side of the plate 128. The washer 142 isthen positioned on the shaft, and the nut 141 is threaded on the end ofthe shaft to clamp the washer 142 against the other side of the plate128.

Positioned coaxially over the shaft 137 is a cylindrical tube 143 whichhas one end secured to an inner end plate 144 adjacent the mountingplate 128, and its other end secured to an outer end plate 146, the twoplates 144 and 146 having axial holes 147 formed therethrough whichreceive the shaft 137. Bearings 148 are preferably provided between theend plates 144 and 146 and the shaft 137.

To rotate the tube 143 relative to the shaft 137, a sprocket 149 isrotatably positioned around the shaft 137 between the end plate 144 andthe mounting plate 128 and is connected to the plate 144 by a slipclutch arrangement. The clutch comprises a disc 151 secured to the outerperiphery of a hub portion of the sprocket 149 and a disc 152 offriction or brake material such as rubber positioned between the disc151 and the end plate'144. The adjacent surfaces of the disc 151 and theplate 144 are substantially flat and parallel to each other, and thefriction disc 152 transmits rotative motion from the disc 151 to the endplate 144.

To prevent the disc 151 and the sprocket 149 from moving axially awayfrom the tube 143, a thrust bearing 153 is mounted on the shaft 137between the sprocket 149 and the mounting plate 128. One race of thethrust bearing 153 abuts the mounting plate 128 while the other race ofthe thrust bearing 153 abuts the sprocket 149. Thus, axial pressuretending to move the tube 143 toward the mounting plate 128, causes anaxial thrust to be exerted on the end plate 144, the friction disc 152,the disc 151, the sprocket 149, the thust bearing 153 and the stationarymounting plate 128. The thrust bearing 153 thus permits the sprocket 149and the tube 143 to rotate freely relative to the mounting plate 128 inspite of such an axially directed thrust.

It will be apparent that the amount of such an axially directed forcedetermines the extent of the frictional coupling between the disc 151and the end plate 144, and consequently the amount of slip between thesetwo members when the sprocket is being driven. The axially directedthrust may be adjusted by means of a hand wheel or knob 154 threaded onthe free end of the shaft 137. A compression spring 156 is positionedbetween the knob 154 and the outer end plate 146, and when the knob 154is threaded on the shaft 137, the spring 156 is compressed and urges theend plate 146 and the tube 143 toward the right, and thereby increasesthe frictional coupling between the disc 151 and the plate 144. If it isdesired to decrease the amount of frictional coupling between the disc151 and the end plate 144, the knob 154 is turned to move it to theleft, which reduces the compressive force on the spring 156.

The knob 154 may be secured to the shaft 137 at an axially adjustedposition by a set screw 158 which is threaded into a radially extendinghole 159 formed in the knob 154. A nylon plug 161 is perferablypositioned between the set screw 158 and engages the threads of theshafts 137. Since the spring 156 is stationary relative to the shaft137, while the plate 146 rotates relative to the shaft 137, a washer 162is preferably positioned between the plate 146 and the spring 156.

The stripper roller 136 is driven by the motor-gear box unit 124. Achain 163 is trained around the sprocket 149 and another sprocket 164which is secured to the rotating tube 126 of the arbor 122. Thus, whenthe motor-gear box unit 124 is energized, the sprocket 164 and the filmsupply roll mounted on the arbor 122 are rotated in the counterclockwisedirection as seen in FIG. 1, and rotation of the sprocket 164 drives thechain 163 and the sprocket 149 also in the counterclockwise direction.Further, the tooth ratio of the sprockets and the diameter of the tube143 are such that, if there were a direct drive between the disc 151 andthe plate 144, the surface speed of the tube 143 would be slightlygreater than the surface speed of the largest size film supply rollnormally used. During the operation of the film feed and transportmechanism 57, the film supply roll 23 is slipped over the arbor 122 andsecured thereto by turning the knob 133. The supply roll is mounted withits free end extending upwardly from the rearward side of the roll, andthe film is threaded from the roll 23 upwardly and over the stripperroll 136 from the rearward side thereof, then forwardly of the machineunder and around the forward side of a stationary laterally extendingroller 166 which is secured to the frame 50, over the top of the roller166 and rearwardly of the machine, under and around the rearward side ofa tension roller 167 (FIG. 1), over the top of the roller 167, and thenforwardly of the machine and over the upper surface of the plate 168. Asexplained in the previously mentioned Hansen et a1. application, thetension roller 167 extends laterally of the machine and is rotatablymounted at the ends of two laterally spaced tension arms or levers whichare fastened to and rotate with a shaft 169. The shaft 169 is alsorotatably supported by the mounting plate 128, and one end of the shaft169 carries a cam (located on the side of the plate 128 which is notshown in FIG. 1). The cam is connected to actuate a switch forcontrolling the motor-gear box unit 124. The cam and switch arrangementis such that the unit 124 is turned on when the arms 170 swing in thecounterclockwise direction and reach a first predetermined position, andthe unit 124 is turned off when the arms 170 swing in the clockwisedirection and reach a second predetermined position. A spring (notshown) urges the arms 170 in the clockwise direction thereby maintainingtension on the film and holding the film against the stripper roller136, and the pull of the film during a wrapping cycle urges the arms inthe counterclockwise direction. During the operation of the machine, thefilm 121 is drawn into the wrapping mechanism as each article is beingwrapped and the consequent pull on the film 121 swings the tensionroller 167 and the arms 170 in the counterclockwise direction as seen inFIG. 1. When the shaft 169 and the arms 170 reach the firstpredetermined angular position, the cam attached to the end of the shaft169 closes the control switch for the motor-gear box unit 124. Uponenergization of the unit 124, the arbor 122 is rotated in thecounterclockwise direction as seen in FIGS. 1 and 3. Further, due to thechain and sprocket connection between the anbor 122 and the stripperroller 136, the stripper roller 136 is also rotated in thecounterclockwise direction as seen in FIGS. 1 and 3. As previouslystated, the surface speed of the stripper roller tends to be slightlygreater than the surface speed of the film supply roll 123 when the roll123 is fresh and, consequently, has a relatively larger diameter, butthe film frictionally engages the surface of the stripper roller 136 andcauses the surface speed of the roller 136 to be substantially the sameas the film speed. The restraining effect of the film on the stripperroller 136 results in slip of the slip clutch, and the amount of slipincreases as the diameter of the supply roll decreases. Further, theamount of tension on the film between the supply roll and the stripperroller may be adjusted by adjusting the tension on the spring 156, usingthe knob 154. Due to the tendency of the stripper roller 136 to turnfaster than the supply roll, the former strips or pulls the film fromthe supply roll 123. To increase the frictional coupling between thestripper roller 136 and the film 121, a plurality of bands 171 (FIGS. 2and 3) of a friction material are fastened to the outer periphery of thetube 143. Annular grooves 172 are formed in the outer periphery of thetube 143, which receive the bands 171.

From the tension roller 167, the film 121 is threaded over the top ofthe plate 168 (FIGS. 1, 5 and 6) underneath a one way check mechanism176 which is mounted on the frame of the machine over the upper surfaceof the plate 168. The check mechanism 176 permits movement of the film121 in the forward direction but pinches the film 121 against the plate168 when there is a tendency for the film 121 to move rearwardly, aswhen the film 121 is pulled by the tension roller 167 and the tensionarms 170. At the forward edge of the plate 168 is positioned a laterallyextending stationary draper shaft 177, and the film 121 normally extendsdownwardly over the forward side of a shaft 177. When the wrappingmachine is idling between packages, the film 121 normally extendsdownwardly around the forward side of the shaft 177, past the rearwardside of a dancer roller 178, and between the adjacent edges of the twoelevators 71 and 72 when in their intermediate positions. The free endportion of the film 121 is held by a suction bafile plate 179 (FIGS. 5,6 and 9) which extends laterally of the machine and is secured to theframe as by brackets 181. The baffle plate 179 comprises a verticallyextending back 182 and a horizontal shelf 183 which extends forwardlyfrom the lower edge of the back 182. The shelf 183 has a hollow interiorwhich forms a suction box (FIG. 5), each end of the shelf 183 beingconnected by a length of hose 184 (FIG. 9) to means, such as a motordriven fan, for producing a partial vacuum. The top side of the shelf183 has sets of holes 185 formed therein, and air is drawn into theinterior of the hollow shelf 183 through the holes 185. This suctiondraws the film 121 to the shelf 183 and holds the free end portion ofthe film 121 flat against the shelf 183, thereby preventing curling ofthe free end of the film 121 and also preventing curling of the verticaledges of the film adjacent its free end.

The dancer roller 178 also extends laterally of the machine and mountedbetween two pairs of vertically extending guides 191 and 192 (FIGS. 1and 5), the pair 191 of guides being located at one side of the machineand the pair 192 of guides being located at the other side of themachine. The guides of each pair are longitudinally spaced to form avertical slot at each side of the machine, and the ends of the dancerroller 178 extend into the slots. The dancer roller 178 is verticallymovable within the slots and, during different portions of each wrappingcycle, is supported either by a pair of lifts 193, a pair of stationarystops 194, or a pair of movable stops 196.

As shown in FIG. 5, the two lifts 193 are secured to the bottom elevator71 and extend upwardly and forwardly from the forward edge of plate 78.As shown in FIGS. 6 and 7, the lifts 193 are spaced laterally inwardlyfrom the guides 191 and 192, and the upper ends of the lifts are adaptedto engage sleeves of the dancer roller and lift the dancer roller 178upwardly upon movement of the bottom elevator 71 to the intermediateposition. Such upward movement of the dancer roller during each wrappingcycle is desirable because it is then out of the way and permits anarticle to be transferred from the bottom elevator 71 to the topelevator 72 while the two elevators are at the intermediate position.Resilient bumpers 197 are preferably secured to the upper end surfacesof the lifts 193 to cushion the impact of the lifts 193 with the sleeves190 when the lifts 193 move upwardly and engage the dancer roller 178.

One of the stationary stops 194, which may comprise ring shaped members,is positioned in the slot between the pair of guides 191 and the otherof the stops 194 is positioned in the slot between the other pair ofguides 192. The two stops 194 are secured to the guides 191 and 192 asby bolts 198 (FIGS. 6 and 7) at locations such that the dancer roller178, while resting on the stationary stops 194, is spaced a shortdistance above the shelf 183 of the suction baffle plate 179, as shownin dashed lines in FIG. 6.

With reference to FIGS. 6 and 7, the movable stops 196 are secured tothe lower ends of a pair of vertically extending levers 201, each of thelevers 201 being associated with and positioned on the forward side ofone pair of guides 191 and 192. Each lever 201 is mounted for pivotalmovement on a lateral axis by a pair of pins 202 which in turn aremounted on blocks 203 secured to the guides 191 and 192 as by bolts 204.The stops 196 extend rearwardly of the machine from the lower ends ofthe levers 201, through holes 206 formed through the adjacent guides 191and 192 and into the slots between the guides.

Above the pivotal connection 202 of each of the levers 201, acompression spring 207 is positioned between the lever 202 and theforwardmost guide of each pair. Grooves 208 are preferably formed in thelevers 201 and the adjacent guides and the ends of the springs 207 areseated in the grooves 208 in order to hold the springs 207 in place. Thecompression springs 207 tend to pivot the levers 201 in thecounterclockwise direction as seen in FIG. 6, and thus to urge the stops196 into the holes 206. Movement of the stops 196 into the holes 206beyond a predetermined amount is prevented however by bumpers 209 (FIG.6) fastened to the forwardmost guides 191 and 192, which extendforwardly from the guide, the bumpers 209 being adapted to abut thelevers 201.

As shown in FIG. 6, the movable stops 196, when they have been pivotedfully in the counterclockwise direction, extend into the slots betweenthe pairs of guides 191 and 192, and the rearward side 211 of each ofthe stops 196 extends into the associated slot and is slanted upwardlyand rearwardly from its lower side.

As shown in FIGS. 6, and 11, the dancer roller 178 includes rectangulardancer roller guide blocks 222 and 223 secured to its ends. Thehorizontal thickness of the outer end portions 222a and 223a of theblocks is reduced and is slightly less than the width of the slots, andthe portions 222a and 223a are positioned in the slots with the verticaldimension of the portions 222a and 223a greater than the horizontalthickness. Thus, the dancer roller 179 may be moved vertically betweenthe guides 191 and 192 but the guides and the portions 222a and 223aprevent turning movement of the dancer roller 178. Further, each of theportions 222a and 223a is slanted at its upper and forward corner 212(FIG. 6).

The lowermost position of the dancer roller 178 is determined by thelocation of the stationary stops 194. Assuming that the roller 178 isinitially resting on the stops 194 and the elevators 71 and 72 are attheir vertically displaced positions, when the bottom elevator 71 movesupwardly the lifts 193 pick up the dancer roller 178. During such upwardmovement, the slanted corners 212 at the ends of the dancer roller 178engage the slanted sides 211 of the two movable stops 196 and cam thestops 196 forwardly. The levers 201 pivot in the clockwise direction asseen in FIG. 6 against the force of the compression springs 207 topermit such forward movement of the stops 196. The dancer roller 178 ismoved upwardly past the stops 196 and then the latter return to theirnormal positions due to the action of the springs 207. The uppermostposition of the dancer roller is indicated in dash-dot lines in FIG. 6,and this position exists when the two elevators 71 and 72 are at theintermediate positions. Thus, the dancer roller 178 is moved upwardlyand held there while an article is being transferred from the bottomelevator 71 to the top elevator 72. Subsequently, the bottom elevator 71moves downwardly and permits the dancer roller 178 to drop due to theforce of gravity. The extent of the downward movement of the dancerroller 178 is initially limited, however, by the movable stops 196 whichengage the bottom sides of the end portions 222a and 223a of the dancerroller 178 and hold it in the intermediate position shown in full linesin FIG. 7. The dancer roller 178 is held in this intermediate positionwhile the article is being transferred from the top elevator 72 to theplate 81. The mechanism which moves the film severing blades 107 afterthe film has been tack sealed, also carries a pair of actuators 216(FIG. 6) which are located to engage the upper ends of the levers 201and pivot the levers 201 in the clockwise direction as seen in FIG. 6.Thus, after the section of film around the article has been tack sealed,the film is severed and the levers 201 are pivoted to cause the movablestops 196 to swing toward the left as seen in FIG. 6, out of engagementwith the ends of the dancer roller 178. The dancer roller again dropsdownwardly to the stationary stops 194, pushing the end portion of thefilm downwardly and laying the film on the suction baffle plate 179.

The dancer roller 178, acting in conjunction with a blow tube 236,prevents the end portion of the film from falling rearwardly upon itselfafter an article has been girdle wrapped and the film has been severed.Just before. the film is severed, the film is draped downwardly on theforward side of the dramr shaft 177 looped under the dancer roller 17 8,and upwardly to the rearward edge of the top elevator. The portions ofthe looped film on the rearward and forward sides of the dancer rolledare relatively close together, and the dancer roller and the blow tubeare constructed to blow air into the space between the looped portionsof the film. This air raises the pressure in this space slightly andwhen the film is severed, the pressure acts on the two portions of thefilm to hold them apart.

With reference to FIGS. 9 to 12, the dancer roller 178 comprises a tube221, preferably made of a material such as stainless steel, and theblocks 222 and 223 secured to the ends thereof. The block 222 is securedto one end of the tube 221 as by a roll pin 224 and the other block 223is secured to the opposite end of the tube 221 as by a set screw 226.The block 222 closes the associated end of the tube 221 and the otherblock 223 has a radially extending hole 227 formed thereon, whichreceives a relatively small tube 228 (FIG. 11). The interior of theblock 223 is hollowed out to receive the associated end of the tube 221,and the tube 228 is in communication with a hollow interior of the block223 and the interior of the tube 221.

To help to prevent the film from clinging to the dancer roller, aplurality of axially spaced rollers 231, which may be made of a materialsuch as hard plastic, are rotatably positioned on the tube 221. Therollers 231 are held in axially spaced relation as by a plurality ofC-shaped members 232 which are positioned in annular grooves 230 formedin the other periphery of the tube 221. The members 232 are generallysquare in cross section, and the grooves 230 are square shaped toreceive the members 232. A member 232 is located at each end of each ofthe rollers 231, the members 232 being engageable with the ends of therollers 231 and thereby preventing axial movement of the rollers 231relative to the tube 221, but permitting rotative movement of therollers relative to the tube.

In the spaces between adjacent rollers 231, a plurality of radiallyextending holes 233 (FIGS. 11 and 12) are formed through the wall of thetube 221, extending from the interior of the tube to the outer surfacethereof, a set of three holes 233 being shown in each space, and theholes 233 are located relative to the rectangular end portions 222a and223a of the blocks 222 and 223 such that one hole of each set openssubstantially downwardly, another hole of each set opens downwardly andforwardly of the machine, and the third hole of each set opens upwardlyand forwardly of the machine. As will be explained hereinafter, the tube228 is connected to a flexible air hose 277 (FIG. 6) which leads to anair pump, and, during a portion of each wrapping cycle, air is forcedinto the tube 221 and out through the holes 233. The air jets passingthrough the holes 233 are directed to blow the severed end portion ofthe film forwardly and downwardly and thereby prevent this portion fromfalling rearwardly and contacting the portion of the film extendingdownwardly from the draper shaft 177.

To further ensure that the film will not fall rearwardly of the machineafter it has been severed, a laterally extending blow tube 236 (FIGS. 6,7, 9 and 10) is provided to blow the film end forwardly. The blow tube236 is located just forwardly of the stationary draper shaft 177 (FIG.6) and is supported by a pair of brackets 237 which are secured to theframe of the machine and engage the ends of the blow tube 236. Withreference to FIG. 10, the blow tube 236 is closed at one end by a plug238 and is open at the opposite end, the open end being adjacent thetube 228 of the dancer roller 178. Two sets 239 and 241 of holes areformed along the length of the blow tube 236 at axially spacedlocations, the set 239 of the holes facing substantially forwardly ofthe machine and the other set 241 of the holes facing substantiallydownwardly. Again as will be described in more detail hereinafter, aflexible air hose 278 (see FIG. 7) is fastened to the open end of thetube 236 and leads to an air blower or pump, and during a portion ofeach wrapping cycle, air is forced into the tube 236 and out of theholes 239 and 241, and into the space between the adjacent portions ofthe looped film, and thereby prevent the free, severed end portion ofthe film from falling rearwardly of the machine.

The apparatus for supplying air under pressure to the dancer roller 178and the blow tube 236 at the proper portions of each cycle is shown inFIGS. 13, 14 and 14a.

The apparatus comprises a main drive shaft 251 which extends laterallyof the machine and is mounted for rotation on the frame. A main drivemotor 252 is connected through a belt 253 and a gear box 254 to rotatethe main shaft 251. Connected to the shaft 251 are suitable cams and camfollowers, such as the cam 256 and the follower 257, moving theelevators 71 and 72, the cutting blades 106 and various other mechanismsof the machine.

In addition, a cam 258 is clamped to the shaft 251 by means of bolts259, and the cam 258 has two edge cam surfaces which are positioned toengage and actuate two air valves 261 and 262. The valves 261 and 262are re spectively mounted on the plate 51 by means of brackets 263 and264. The valve 261 is connected to control the supply of air to thedancer roller 178 and the valve 262 is connected to control the supplyof air to the blow tube 236.

Also mounted on the frame of the machine are an electric motor 266 andan air pump 267, the motor 266 being connected by a belt 268 to drivethe air pump 267. The drive shaft of the motor may also be connected todrive a device 269 which produces a partial vacuum for the suctionbaffle plate 179. The device 269 may be connected by suitable conduits270 and the hose 184 (see FIG. 9) to operate the suction baffle plate179.

Air from the pump 267 is delivered by a flexible air tube or hose 272 toa T-fitting 273 mounted on the plate 51, for example. The T-fitting 273receives air from the tube 272 and directs it to two other air tubes 274and 276 which are also connected to the inlets of the valves 261 and262, respectively. The outlets of the two valves 261 and 262 arerespectively connected to the two tubes or hose 277 and 278 which supplyair to the dancer roller 178 and to the blow tube 236.

As shown in FIGS. 13 and 14a, the cam 258 has the two previouslyreferred to cam surfaces 281 and 282 formed on its outer periphery. Thecam surface 282 is adapted to engage an actuating button 283 for thevalve 261, which is connected to control the supply of air to the dancerroller 178, and the cam surface 282 is adapted to engage an actuatingbutton for the valve 262, which is connected to control the supply ofair to the blow tube 236. The cam surface 281 is constructed to engagethe button 283, and thereby open the valve 261, during approximately a65 arc in each circle of revolution of the drive shaft 251 and the cam258, and the other cam surface 282 is constructed to engage the button284, and thereby open the valve 262, during approximately a 30 arc ineach circle of revolution. Further, the valves 261 and 262 arepositioned and the cam surfaces 281 and 282 are constructed such thatthe valve 262 for the blow tube is turned on first by the cam surface282 and remains on for approximately a 30 arc of the revolution of thecam 252. Each complete revolution of the drive shaft 251, andconsequently the cam 258, corresponds to one wrapping cycle of themachine. At substantially the same time that the cam surface 282 movesout of engagement with the button 284, and thereby turns off the valve262, the cam surface 281 engages the button 283 and turns on the valve261 for the dancer roller 178. Then, with the valve 262 for the blowtube turned 011, the valve 261 for the dancer roller remains on forapproximately a 65 arc of the revolution of the cam 258. After the cam258 has turned through the 65 arc, the cam surface 281 moves out ofengagement of the button 283 and turns off the valve 261. Both valves261 and 262 then remain off until the cam 258 has turned sufficientlyfar for the cam surface 282 to again move into engagement with thebutton 284 and turn on the valve 262 during the next wrapping cycle. Aswill be explained hereinafter, the operation of the valves 261 and 262is synchronized with the wrapping mechanism such that they are turned onfrom approximately the time that the film is begun to be severed untilthe film is moved to the suction baflile plate 179.

During each wrapping cycle, the top plunger 82 moves rearwardly of themachine and pushes the article from the top elevator 72 rearwardlytoward the plate 81. During such rearward movement of the article, thefilm 121 is folded underneath the article and portions of the filmoverlap. Adjacent the forward edge of the plate 81 is provided a tacksealer 291 (FIGS. 1 and 5) which tack seals the overlapped portions ofthe film before the film is severed. Plastic films tend to stick to hotobjects, and the tack sealer 291 is constructed to eliminate thisdifliculty. The tack sealer 291 extends laterally of the machine at theforward edge of the plate 81, and is mounted in an angle shaped bracket292 (FIGS. 5 to 7) which is secured to the frame of the machine as bybolts. The tack sealer 291 comprises a cylindrical heater cartridge 293fastened to the bracket 292 by blocks 294 which are secured to the endsof the cartridge 293 and to the bracket 292. The cartridge 293 includesa suitable heating element 296, which is connected to an electricalsupply by suitable conductors 297 (FIG. 7). The cartridge 293 furtherincludes a thermostat 298 which is connected in the power supply controlcircuit for the heating element 296. The thermostat 298 may be aconventional type, such as a fluid filled bulb, and is preferablyaccurate enough to hold the temperature of the heating cartridge to amaximum variation of 10 to 15 F It is preferred that the temperature ofthe tack sealer 291 be adjustable within the' range of 200 to 500 F.,depending upon the particular type of film being used.

The tack sealer 291 further includes a thin walled tubular metal roller301 (FIG. 8) which has an inner diameter somewhat greater than the outerdiameter of the heating cartridge 293. The roller 301 is rotatablymounted on the heater cartridge 293 between the two mounting blocks 294which prevent substantial longitudinal movement of the roller 301relative to the heater cartridge 293. Further, a coating 302 ofnon-stick material, such as Teflon, is preferably formed on the roller301, and the roller 301 is preferably made of a high heat conductingmaterial such as aluminum.

During the operation of the machine, energization of the heating element296 causes the cartridge 293 to heat up to operating temperature. Theportion of the roller 301 at the top side of the tack sealer becomeshotter than the other portions because the to portion is in directcontact with the cartridge 293. The remainder of the roller 301 is at alower temperature because it is out of direct contact with the cartridge293, as shown in FIG. 8. As an article is pushed from the top elevator72 toward the plate 81, the rearward edge of the article engages theroller 301 and causes the roller 301 to rotate in the clockwisedirection as seen in FIGS. 6 and 8 as the package moves over the top ofthe tack sealer. Even though the roller 301 is hot, it is notsufliciently hot to damage or seal the film because the article and theroller 301 are moving. With such movement of the article, no one portionof the film remains in contact with the roller 301 for any length oftime, and the movement of the roller, because it is in contact with theheater therein only at the upper side of the roller, results inconstantly changing the portions of the roller that have to be broughtup to heat. Thus, so long as the article and roller are moving,insufiicient heat is imparted to the film to effect sealing. Further,the coating 302 of Teflon helps to prevent the film from sticking to theroller.

After the film has been wrapped around the article and overlapped andthe overlapped portions are over the tack sealer, movement of thearticle is stopped momentarily. With no movement of the article, theroller 301 also stops turning and the upper portion of the roller 301,which is in direct contact with the heating cartridge 293, rapidlybecomes heated to a greater extent. The pause in the movement of thepackage, while the overlapmd portions of the film are over the tacksealer and before the film has been severed, is long enough for theupper portion of the roller to heat up and tack seal the film. Theweight of the 15 article being wrapped presses the overlapped portionsof the film against the roller 301 during the tack sealing operation.

The pause in the movement of the article, during which tack sealingtakes place, may be produced by constructing the cam which moves theplunger 82 such that the plunger, and thus the article, stops while theoverlapped portions of the film are over the tack sealer and then movesrearwardly again to its maximum rearward position. A pause may also beproduced by making the maximum rearward position of the plunger occurwhen the overlapped portions of the film are over the tack sealer, andtiming the movement of transport arms 311, which push the articlesrearwardly after they have been pushed on to the plate 81 by the plunger82, such that the article momentarily remains stationary before the arms311 engage and move the article. In practice, it may be desirable tohave two pauses, and consequently two tack seals, one produced by thecam construction and the other produced by the timing of the plunger 82and the arms 311.

After the film around an article has been scaled and severed, thearticle is pushed by the top plunger 82 onto the plate 81 which formspart of an end folding apparatus 316 (FIGS. 1, 15 and 16). As describedin the previously referred to patent applications, the transport arms311 are arranged in pairs, the arms of each pair being laterally spaced,and are attached to a pair of laterally spaced chains 312 which aretrained around two pairs of sprockets 313 and 314 (FIGS. 1 and 16). Thesprockets are mounted on suitable shafts for rotation on the frame ofthe machine, and are preferably connected by chains and sprockets to bedriven by the main drive motor 252 such that the chains 312 rotatecontinuously during operation in the counterclockwise direction as seenin FIG. 1. The movement of the transport arms 311 is timed with theremainder of the wrapping mechanism such that one pair of the arms 311moves to a position adjacent the forward edge of the plate 81 after eacharticle has been pushed from the top elevator 72 to the plate 81. Aspreviously stated, the timing is preferably such that the article ismomentarily stationary while over the tack sealer after it has beenmoved by the plunger 82 and before it is engaged by the arms 311.

The arms 311 move the articles across the plate 8-1 of the end foldingapparatus 316, which is described in detail in the above Hansen et al.patent application and is partially shown in FIGS. 15 and 16. The endfolding mechanism 316 draws the film tightly in the lateral directionacross the top and bottom sides of the film, and folds the ends of thefilm underneath the article. After the ends of the film have been foldedunder the article, the articles are moved by the transport arms 311 fromthe plate 81 onto a main heat sealer 317 (FIGS. 1, l and 16). The mainsealer 317 comprises a heating element 318 having a fiat, horizontalupper surface 319, and an endless belt 321 which is trained around adrive roller 322 and an idler roller 323. The drive roller 322 isconnected by a chain 324 to be driven from the main drive motor 252 ofthe wrapping machine, the chain 324 preferably also being connectedthrough a sprocket 326 to rotate the sprockets 313 and 314 and thetransport arms 311. The chain 324 may, for example, mesh with a sprocket327 which in turn is connected by gears to rotate the drive roller 322in the clockwise direction as seen in FIGS. 1 and 15. The belt 321 isdriven by the roller 322 in the clockwise direction, and the belt 321engages and sweeps across the upper surface 319 of the heater 318. To

maintain tension on the belt 321, atension member 328 is connected tothe lower end of a tension bar 329 which is pivotally mounted on theframe of the machine by a pin 331. The member 328 engages the innersurface of the belt 321 and presses the lower portion of the beltdownwardly, and thereby tensions the belt 321.

To ensure that the film on the underside of the article is pressedfirmly against the belt 321, two pairs of rollers 332 are mounted on theframe of the machine above the main sealer 317 and adjacent thelongitudinally extending sides thereof. As explained in the previouslymentioned Hansen et al. patent application, the articles are moved overthe main sealer underneath the rollers 332, which are mounted such thatthey may swing upwardly in the counterclockwise direction as seen inFIG. 15 as the longitudinally extending sides of the articles moveunderneath the rollers 332, and the weight of the rollers 332 pressesthe article firmly against the main sealer 317.

During the operation of the end folding apparatus 316 and the mainsealer 317, the transport arms 311 move the articles along the plate 81of the apparatus 316 where the ends of the film are folded underneaththe article, and onto the main sealer 317. The belt 321 is rotated suchthat its surface speed is the same as the speed of the article. The belt321 is preferably made of fiber glass which is impregnated with Teflon,the Teflon again preventing or reducing the chance that the belt 321will stick to the film on the underside of the article. The portion ofthe belt 321, between the article and the main heater 318, becomesheated by the heater 318 and it transfers the heat to the filmunderneath the article and seals the film.

At the rearward end of the main heater 317 may be provided an outputconveyor 326 (FIG. 1). The transport arms 311 move the article past themain sealer 317 and to the output conveyor 326, and the latter conveyor326 may carry the articles either to a bin or to an input of a transportand labeling machine. The conveyor 326 may have either a positive drivefor moving the articles from left to right as seen in FIG. 1 or it maybe inclined sufficiently for the articles to move along it due to theforce of gravity.

FIGS. 17 to 23 illustrate schematically the successive stages in onewrapping cycle when an article 341 is girdle wrapped in the film 121.The stage shown in FIG. 17 occurs just after the article 341 has beenmoved from the infeed conveyor mechanism 54 onto the bottom elevator 71.At the same time, a preceding article 342 has been moved off from thetop elevator 72 and onto the plate 81 of the end folding apparatus 316.The two elevators 71 and 72 are at their vertically displaced positions,and the free end of the film 121 is on the shelf 183 of the suctionbaffle plate 179 and is being held thereby. The dancer roller 178 isbeing supported by the stationary stops and both air valves 261 and 262are turned off.

In FIG. 18, the two elevators 71 and 72 have been moved to theintermediate positions where they are horizontally aligned. The lifts193 attached to the bottom elevator 71 engage the underside of thedancer roller 178 during upward movement of the bottom elevator 71 andlift the dancer roller upwardly, to the position shown in FIG .18, wherethe bottom plunger 83 may move the article from the bottom elevator 71to the top elevator 72, as shown in FIG. 19. As the article 241 is beingtransferred from one elevator to the other, it engages the film andslides over the free end of the film 121, as it slides onto the topelevator 72. The free end portion of the film 121 is drawn off of theshelf 183 of the suction baffle plate 179 as the article 341 is pushedonto the top elevator 72. As shown in FIG. 19, the dancer roller 178 isstill in the raised position where it is supported by the lifts 193.

After the article 341 has been transferred to the top elevator 72, thetwo elevators 71 and 72 shift to their vertically displaced positions(FIG. 20), and the film is folded over the top of the article 341 anddownwardly on its rearward side. From the rearward side of the article341, the film 121 extends downwardly and underneath the dancer roller178, and then upwardly to the stationary draper shaft 177 and over theplate 168. When the bottom elevator 71 moves downwardly, the lifts 193permit the dancer roller 178 to drop until the blocks at the ends of thedancer roller 178 engage the movable stops 196. The

